Abstract

Carbon contamination levels in the 5–15-at. % range have been observed in optical thin films deposited on graphite substrates for RBS analysis. The lack of large amounts of carbon in films grown on beryllium indicates that substrate carbon migrates along columnar boundaries and rests in the voids of films evaporated onto graphite. We originally believed that this excess carbon nullified the RBS results but have found that the stoichiometry and density of films deposited on both C and Be substrates were essentially the same. The depth profile of the carbon contamination then serves as a probe of relative film porosity without interfering with the other elemental determinations.

© 1985 Optical Society of America